HD74BC640A

HD74BC640A Octal Bus Transceivers With 3 State Outputs ADE-205-026 (Z) Rev.0 June 1993 Description The HD74BC640A provides high drivability and operation equal to or better than high speed bipolar standard logic IC by using Bi-CMOS process. The device features low power dissipation that is about 1/5 of high speed bipolar logic IC. When the frequency is 10 MHz. The device has eight bus transceivers with three state outputs in a 20 pin package. Each device has an active low enable input ( G ) and a direction control input, DiR. When DiR is high, data flows from the A inputs to the B outputs. When DiR is high, data flows from the B inputs to the A outputs. When enable inputs (G) is high, disables both A and B ports by placing then in a high impedance. Features Input/Output are at high impedance state when power supply is off. Input pins can be open, when not used, owing to built in input pull up circuit. Input is TTL level. Wide operating temperature range Ta = –40 to +85°C. Function Table Control Inputs G L L H H : L : X : High level Low level Immaterial DIR L H X Operation B data to A bus A data to B bus Isolation HD74BC640A Pin Arrangement DiR A1 A2 A3 A4 A5 A6 A7 A8 GND 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 VCC G B1 B2 B3 B4 B5 B6 B7 B8 (Top view) Absolute Maximum Ratings Item Supply voltage Input diode current Input voltage Output voltage Off state output voltage Storage temperature Note: Symbol VCC I IK VIN VOUT VOUT(off) Tstg Rating –0.5 to ...